http request javascript

                                    function httpGetAsync(url, callback) {
  var xmlHttp = new XMLHttpRequest();
  xmlHttp.onreadystatechange = function() { 
    if (xmlHttp.readyState == 4 && xmlHttp.status == 200)
      callback(xmlHttp.responseText);
  }
  xmlHttp.open("GET", url, true); // true for asynchronous 
  xmlHttp.send(null);
}

                                    // Use these functions:

function _GET_REQUEST(url, response) {
  var xhttp;
  if (window.XMLHttpRequest) {
    xhttp = new XMLHttpRequest();
  } else {
    xhttp = new ActiveXObject("Microsoft.XMLHTTP");
  }

  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      response(this.responseText);
    }
  };

  xhttp.open("GET", url, true);
  xhttp.send();
}

function _POST_REQUEST(url, params, response) {
  var xhttp;
  if (window.XMLHttpRequest) {
    xhttp = new XMLHttpRequest();
  } else {
    xhttp = new ActiveXObject("Microsoft.XMLHTTP");
  }

  xhttp.onreadystatechange = function() {
    if (this.readyState == 4 && this.status == 200) {
      response(this.responseText);
    }
  };

  xhttp.open("POST", url, true);
  xhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  xhttp.send(params);
}


// Use like:
_GET_REQUEST('http://url.com', (response) => {
	// Do something with variable response
  	console.log(response);
});
_POST_REQUEST('http://url.com', 'parameter=sometext', (response) => {
	// Do something with variable response
  	console.log(response);
});

                                    <script>
function loadDoc() {
  var xhttp = new XMLHttpRequest();
  
  //looking for a change or state , like a request or get.
  xhttp.onreadystatechange = function() {
     
     //if equal to 4 means that its ready.
    // if equal to 200 indicates that the request has succeeded.
    if (this.readyState == 4 && this.status == 200) {
      document.getElementById("demo").innerHTML = this.responseText;
    }
  };
  
  //GET method for gettin the data // the file you are requesting
  xhttp.open("GET", "TheFileYouWant.html", true);
  
  //sending the request
  xhttp.send();
}